JP2764015B2 - Method for producing a synthetic resin plate having a grain pattern - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermoplastic synthetic resin plate having a grain pattern used for various building materials.

[0002]

2. Description of the Related Art As a simple method for producing a synthetic resin plate having a wood grain pattern, for example, as disclosed in Japanese Patent Publication No. 3-59804, a molding resin material made of a thermoplastic resin mixed with wood powder is used. Circular die (round die)
A method is known in which the material is once extruded into a tube shape, cut open in the extrusion direction, and developed into a flat plate shape to obtain a plate-shaped material.

[0003] However, such a manufacturing method has one inherent serious problem. That is, the circular die is a die shell in which a topeed or mandrel is connected and supported in a suspended state through several or more spider portions in the circumferential direction, and the outer surface of the topedo and the inner surface of the die shell are connected to each other. An annular resin flow path is formed therebetween, and the molding resin material is sent out toward the die slit portion at the tip. For this reason, the resin material is once divided by the spider portion in the annular flow path, and then merged again to be integrated by fusion. However, this fusion line portion has a weak point in mechanical strength such as tension or bending. It remains at a plurality of locations in the circumferential direction as a part. Therefore, even in the synthetic resin plate obtained by expanding the extruded tube, the weak point portion on the strength is embedded in a form continuous in the length direction at a plurality of positions in the width direction,
When the synthetic resin plate is subjected to thermoforming such as vacuum forming or pressure forming, there is a possibility that breakage may occur during thermoforming. Specifically, for example, it was not able to withstand thermoforming at a molding magnification of 3 times, and there was a problem that the usage was restricted.

[0004] On the other hand, in the production of a synthetic resin plate by the above-mentioned extrusion development method, various methods for imparting a grain pattern similar to natural wood to the surface thereof have been conventionally studied. One of the most promising methods is Tokuho 3-5.
As shown in Japanese Patent No. 9803, a plurality of bridges that cross the flow path are provided at the resin outlet of the circular die of the extruder, and the use of the fact that the flow of the resin is obstructed by the bridges is utilized. Thus, a method has been proposed in which a plate pattern is provided on the surface of a developed plate material.

[0005] However, in this method, for the same reason as the strength problem caused by the spider described above,
In addition, weak points in strength remained in many places, and not only thermoforming workability but also practically hindered use in the flat state. In addition, in the above-mentioned proposed method, the surface skin becomes bad, and in practice, only the woodgrain pattern can be satisfactorily applied in the woodgrain pattern, and the straight-grained pattern which is preferably viewed in appearance is obtained. It was difficult to give.

[0006] On the other hand, the applicant of the present invention disclosed in Japanese Patent Application No. 6-40186 filed in the earlier application a molding resin material mixed with particles of a colorant such as brown for giving a grain pattern. In addition to the use, a surface friction means having an uneven shape is provided on a part of an inner peripheral surface or an outer peripheral surface of an annular resin passage in a circular die for extrusion, and a flow friction resistance is applied to the surface of the resin material. The present invention has proposed a method of giving a pattern oriented on the surface of a molded article in the extrusion direction of the coloring material to give a straight grain pattern.

[0007] The above-mentioned prior proposal method has been sufficiently satisfactory in the desired effect of imparting a straight grain pattern.
Furthermore, it was regrettable to have the following problems.

That is, the straight-grain pattern formed by the above method has a depth of 0.1 in only the surface layer of the artificial wood.
It is only formed in an extremely shallow range of about 0.2 mm. For this reason, when the surface of the artificial wood is polished or cut depending on the application, the straight grain pattern may easily disappear.

[0009]

SUMMARY OF THE INVENTION In the technical background as described above, the present invention relates to a method of manufacturing a synthetic resin plate by an extrusion expansion method. We shall not leave the weak points of the surface, and also give a beautiful wood grain pattern to the plate surface to a certain depth deep on the assumption that it is easy to grind the plate surface To have a wood grain pattern that does not disappear, and furthermore, there is a freedom of choice such as making the wood grain pattern have a change similar to natural wood or forming a good-looking straight grain pattern It is an object of the present invention to provide a method for manufacturing a synthetic resin plate having a wood grain pattern that can satisfy the above-mentioned various requirements.

[0010]

SUMMARY OF THE INVENTION In the above object, the present invention is based on the premise that a molding resin material mixed with a coloring material for giving a grain pattern is extruded by an extruder equipped with a circular die. After extrusion molding into a tube having a diameter, the extruded tube is cut at one point in the circumferential direction in the extrusion direction and expanded to obtain a flat synthetic resin plate. Using a die connected and supported on the outer shell by one spider part at one place in the direction, the tube extruded from the die is moved along the resin fusion line by the spider part at the fusion line or at a position near the fusion line. The gist of the present invention is a method for manufacturing a synthetic resin plate having a grain pattern, which is characterized by cutting.

As an additional means for imparting a good and deep wood grain pattern to the surface of the synthetic resin plate of the product, an outer peripheral surface at an intermediate portion in the extrusion direction into an annular resin flow path in the circular die is provided. Or, using a die provided with a resistance member having a large number of fins or protrusions projecting inward from the inner peripheral surface side, by the spreading orientation of the coloring material in the molding resin material by the fins or protrusions, the extruded tube It is proposed that at least one of the inner and outer surfaces is provided with a grain pattern.

Further, in order to form the wood grain pattern into a straight grain pattern which is more preferable in appearance, means for providing the fins or projections in a dense arrangement with a pitch of 1 to 30 mm is employed.

Furthermore, in order to provide a synthetic resin plate as artificial wood and to provide workability and appearance similar to natural wood, as a molding material, a thermoplastic synthetic resin together with the coloring material is used together with 100 parts by weight of resin. It is recommended to use a powder obtained by adding and mixing 10 to 100 parts by weight of powder.

Hereinafter, the structure of the present invention will be described in detail with reference to the accompanying drawings.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the molding resin material used in the present invention is based on a blend of a thermoplastic synthetic resin, preferably a mixture of wood flour, and a brown-based resin for forming a grain pattern thereon. And the like.

The thermoplastic resin is not particularly limited, but specific examples thereof include polyvinyl chloride resin (PVC), acrylonitrile-butadiene-styrene copolymer resin (ABS), and polystyrene resin (P
S), polypropylene resin (PP) or the like is used. Wood flour has a particle size of 80 to 300 mesh and a moisture content of 1 to 5
% Is preferably used. The compounding amount is preferably about 10 to 100 parts by weight, more preferably 30 to 70 parts by weight, based on 100 parts by weight of the thermoplastic resin.

The coloring material is a thermoplastic resin powder or pellet colored darker than the base material composed of a mixture of the above resin and wood flour, and has good compatibility with the resin of the base material. It is preferable to use those having the same quality. As an example of the brown coloring material, for example, "WR-PVC, W-3" manufactured by Central Glass Co., Ltd.
2C, H244 "(trade name) can be listed as a suitable product. The mixing ratio of the coloring material depends on the base material 10
2 to 6 parts by weight, particularly preferably 3 to 5 parts by weight, per 0 parts by weight.
Good results can be obtained by setting the amount to about parts by weight.

In the production of the synthetic resin plate according to the present invention, the resin material for molding is used to extrude it into a tube once by an extruder (1) equipped with a circular die (2) as shown in FIG. After that, this extrusion tube (1
0) is cut at a position in the circumferential direction by the cutting blade (3) at a position near the exit of the die, and is opened in a developed state to form a flat synthetic resin plate (P). After the development, in order to remove the stress strain remaining inside, it is preferable to further carry out a compensation process for stabilizing by passing through a hot roll.

In the above extrusion molding, the present invention provides a circular die (2), as shown in FIGS. 1 and 3, a topeed (7) having one spider portion (5) at one circumferential position. The die connected and supported by the die outer shell (6) is used.

That is, an opening (8) for an annular flow path (8) of a spider ring (4) in which an outer ring part (4a) and an inner ring part (4b) are connected and fixed to a die shell (6) and a topeed (7), respectively.
Inside, a bridge-shaped spider portion (5) is provided only at one location in the circumferential direction. The spider section (5) is preferably formed to have a streamlined cross section so as not to hinder the flow of the resin as much as possible. In addition, in order to secure a sufficient supporting force of the topeed (7), it may be formed to be much longer in the lengthwise direction of the topeed than in the illustrated state.

By providing the spider portion (5) at only one circumferential position of the annular flow path (9) in the die, the extruded tube (10) can be formed in the circumferential direction. The resin fusion wire based on the presence of the spider portion (5) is held at only one location. Therefore, the cutting blade (3) is arranged at a position corresponding to the spider portion (5), and the extruded tube is cut along the fusion line at or near the fusion line, and is developed. The synthetic resin plate (P) to be a product can have a uniform strength distribution over the entire width thereof. That is, the fusion line portion which is a weak point in strength is located on both side edges or both side edges of the resin plate, so that a resin plate (P) which is not inferior in strength can be obtained. .

Next, as a means for giving an arbitrary grain pattern to the resin plate (P), the circular die (2) used in the present invention further comprises one or more ring-shaped resistance members (11) ( 12) shall be equipped.

One of the ring-shaped resistance members (11) is provided on the topeed (7) side so as to impart a grain pattern to the inner surface of the extruded tube (10), and the other ring-shaped resistance member is provided. (12) is provided on the die shell (6) side so as to give a grain pattern to the outer surface side of the extrusion tube (10). Each of them is disposed adjacent to the downstream side of the spider ring (4) in the flow direction of the resin flow path (9), but is not limited to this position. The spider ring (4) may be arranged on the upstream side or may be arranged on the downstream side of the spider ring (4). However, in the annular resin flow path (9) between the torpedo (7) and the die shell (6), it is necessary to dispose it at an intermediate region upstream of the die slit (9a) at the tip thereof. is there. When provided in the die slit (9a) portion, the resistance member (11)
The effect of the scratches due to (12) remains strongly on the plate surface, and the surface of the resin plate (P) to be molded becomes poor, and the mechanical strength may be low.

Incidentally, the inner resistance member (11) on the side of the torpedo (7) is formed for providing a plate pattern in the illustrated example, and has a pitch on the outer peripheral surface as shown in FIG. A plurality of resistance projections (13) protruding into the annular resin flow path (9) are provided at equal or irregular intervals of about 30 to 100 mm. In the illustration, the protrusion for resistance (13)
Is a height of 2 with respect to the spacing or flow path width of the resin flow path (9).
0 to 80%, preferably about 30 to 50%, thickness 1 to
It is preferably formed in a flat plate shape of 5 mm, preferably about 2 to 3 mm, but may be formed in another shape such as a columnar shape, a prismatic shape, a pyramid having a triangular cross section, or a needle.

The resistance projection (13) is formed in the annular resin flow path (9).
The flow resistance is given to the resin material flowing inside, and the flow of the resin material becomes relatively faster between the adjacent protrusions (13) and (13). A plate-like pattern (P1) as shown in FIG. Therefore, by setting the interval between the adjacent resistance protrusions (13) and (13) to be unequal in the circumferential direction, it is possible to provide a pattern that varies in the width direction of the resin plate (P). Thus, a pattern more similar to the grain pattern of natural wood can be formed.

The smaller the pitch of the resistance projections (13), the more the pattern to be applied can be changed to a pattern close to a straight-grain pattern.

From this, the outer resistance member (12) on the other die outer shell (6) side is formed in order to give a straight grain pattern in the illustrated example, and the pitch is formed on the inner peripheral surface. At intervals of 1 to 30 mm, preferably 3 to 15 mm,
A large number of fins (14) having a tapered triangular cross section are projected. The height of this fin (14)
It is formed in a range of about 20 to 90%, preferably about 40 to 60% with respect to the interval of the resin flow path (9).

The fin pitch determines the mode of the grain pattern given to the board surface. When the fin pitch exceeds 30 mm, the fin pitch no longer has the appearance of a straight grain pattern.
The pitch should be set lower than that. On the other hand, if the pitch is less than 1 mm, the fins cannot be provided with the required strength, or the fins have a low height. Can not. Preferably, the pitch is set to about 3 to 15 mm.

The resin material flowing in the annular resin flow path (9) is subjected to flow resistance on the outer peripheral surface by the fins (14), and the coloring material contained in the material is spread in a fine pitch at a fine pitch in the flow direction. As shown in FIG.
A grain pattern similar to natural wood as shown in (a) (P2
) Is given.

In the illustrated embodiment, two resistance members (11) and (12) of different types are arranged inside and outside to face each other. However, the same type for applying a grain pattern or a straight grain pattern is used. The two resistance members may be arranged. Further, the two resistance members (11) and (12) may be arranged at different locations in the flow direction of the resin material. Further, only one of the inner and outer resistance members may be provided so that a grain pattern (P1) or a straight grain pattern (P2) is provided on only one surface of the resin plate (P).

[0031]

EXAMPLES As a resin material for molding, 100 parts by weight of a base material composed of a mixture of 100 parts by weight of polyvinyl chloride resin and 30 parts by weight of dry wood flour having an average particle diameter of 100 μm were mixed with a brown coloring material (Central Glass). "W
R-PVC ”) in which 4 parts by weight were mixed.

On the other hand, as an extruder, a caliber of 55 mm, L / D
= 18, equipped with a circular die (2).

As shown in FIG. 1, the circular die (2) has a torpedo (7) supported at one circumferential position by a spider ring (4) having one spider portion (5). A cutting blade (3) is provided at a position close to the front of the resin outlet at the corresponding position of (5). Also, the annular die slit (9d) of the die (2)
Has a diameter of 380 mm, a slit width of 3.0 mm, and a channel width of 10 mm in the middle region of the annular resin channel (9).

On the other hand, two inner and outer resistance members (11) and (12) are provided adjacent to the rear of the spider ring (4). One inner resistance member (11) is provided with a plurality of resistance projections (height 3mm, thickness 2mm, length 3mm) (13) on the inner surface in the circumferential direction at unequal intervals with a pitch of 30 to 60mm. The other outer resistance member (12) has a plurality of tapered triangular cross-section fins (height 8 mm, base end thickness 1.92 mm, length 3 mm) at intervals of 3.5 mm in the circumferential direction of the inner surface. (14)
Was provided.

The extruder (1)
Into a tube (10) having a diameter of 380 mm and a wall thickness of 3 mm. Here, the extrusion conditions were as follows: the temperature of the hopper of the extruder was 170 ° C., the temperature of the outlet of the cylinder (1a) was 175 ° C., the temperature of the screw (1b) was 170 ° C., the temperature of the adapter (15) was 175 ° C., and the circular die ( 2)
At a temperature of 180 ° C. and a screw rotation speed of 20 rpm.

Next, the formed tube (10) extruded from the circular die (2) is cut open at one circumferential position at a position corresponding to the spider portion (5) by a cutting blade (3) provided near the die outlet. After being developed into a sheet, the mixture was allowed to cool and cool to obtain a flat synthetic resin plate product having a width of 1050 mm and a thickness of 3 mm.

As shown in FIGS. 2 and 6, this synthetic resin plate (P) has a beautiful straight grain pattern (P2) on the outer surface of the extruded tube (10), which is similar to natural wood.
The back surface formed by the inner surface of the extruded tube (10) had a grain pattern (P1) arranged at irregular intervals in the board width direction.

Then, when each of the front and back surfaces of the synthetic resin plate material (P) was polished to an average depth of 1.0 mm, a straight-grain pattern (P2) and a plate-grain pattern (P1) were obtained on each surface. Remained in a beautiful state without disappearing.

Next, when the above-mentioned synthetic resin plate (P) was used as a test material and subjected to thermoforming using both vacuum and air pressure, the test material still did not break in thermoforming at a molding magnification of 3 times. It was confirmed that the thermoformability was good. By the way, in the case of a synthetic resin plate molded under the same conditions as in the above example using a conventional circular die having six spiders in the circumferential direction, if the thermoforming is performed at a molding magnification of 3 times, the spider mark portion is formed at the time of molding. The sheet material was torn at the fusion wire portion corresponding to the above.

[0040]

According to the first aspect of the present invention, in the production of a synthetic resin plate having a woodgrain pattern by the extrusion development method, a circular die tope used is supported by only one spider portion in the circumferential direction. As a result, only a fusion line, which is a weak point in strength, occurs only at one location in the circumferential direction of the extruded tube. Moreover, the fusion line is cut along the fusion line,
Since it is developed to be a flat synthetic resin plate, the resin plate does not have a portion that is a weak point in relative mechanical strength in the width direction, and is further more compared with the conventional manufacturing method. It is possible to obtain a synthetic resin plate which is excellent in strength and which is not restricted by a range of applications in which thermoformability is good.

According to the second aspect of the present invention, in the case where the step having a wood grain pattern is used, the synthetic resin sheet has a wood grain pattern or a straight grain wood grain pattern at a relatively deep position on the board surface. You can get a board. Moreover, since the wood grain pattern is given by applying resistance to the surface of the resin material with fins or resistance projections in the intermediate region of the annular resin flow path in the circular die, the resin comes out of the die slit. At this point, the surface skin of the extruded tube is restored to a good state, and a synthetic resin plate having good appearance and strength can be obtained.

Further, in the present invention, the surface of the synthetic resin plate may be provided with a preferable grain pattern in appearance, and the grain pattern does not disappear even by surface polishing or the like. It can be.

Further, in claim 4, a synthetic resin which has the same good workability as wood for cutting, cutting and the like, and is further excellent in suitability for use as artificial wood having an appearance and texture similar to a wooden skin. You can get a board.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of an extruder provided with a circular die used for carrying out the present invention.

FIG. 2 is a perspective view showing a mode in which the extruded tube is cut open and developed into a plate shape.

FIG. 3 is a sectional view taken along line III-III of FIG. 1;

FIG. 4 is a partial cross-sectional plan view of the topedo as viewed from above along line IV-IV in FIG. 1;

FIG. 5 is a sectional view taken along line VV of FIG. 1;

FIGS. 6A and 6B show a pattern of both sides of a synthetic resin plate to be manufactured, wherein FIG. 6A is a front view and FIG. 6B is a rear view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Extruder 2 ... Circular die 3 ... Cutting blade 4 ... Spider ring 5 ... Spider part 6 ... Die shell 7 ... Toped 9 ... Annular resin flow path 10 ... Extruded tube 11 ... Inner resistance member 12 ... Outer resistance member 13 ... Resistance protruding portion 14: Fin P: Synthetic resin plate P1: Plate pattern P2: Straight grain pattern

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI B29C 69/00 B29C 69/00 // B29K 511: 14 B29L 7:00 (56) References JP 3-59804 (JP, B2) Tokiko Hei 3-59803 (JP, B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) B27N 3/28

Claims (4)

(57) [Claims] 1. A resin material for molding mixed with a coloring material for imparting a grain pattern is extruded into a tube having a predetermined diameter by an extruder equipped with a circular die.
In the method of cutting and unfolding the extruded tube in the extruding direction at one location in the circumferential direction to obtain a flat synthetic resin plate, as the circular die, the torpedo is formed by one spider portion at one location in the circumferential direction. Using a die connected to and supported by the outer shell, a wood grain pattern characterized by cutting a tube extruded from the die along the resin fusion line by the spider portion at or near the fusion line. Of manufacturing a synthetic resin plate having the same. 2. A circular die including a resistance member having a plurality of fins or projections projecting inward from an outer peripheral surface or an inner peripheral surface at an intermediate portion in an extrusion direction in an annular resin flow path in the die. By using a die provided, at least one of the inner and outer surfaces of the extruded tube is provided with a grain pattern by the spreading orientation of the coloring material in the molding resin material by the fins or the protrusions. A method for producing a synthetic resin plate having a grain pattern according to claim 1. 3. The production of a synthetic resin plate having a wood grain pattern according to claim 2, wherein the extruded tubes are provided with fins or projections in a dense arrangement with a pitch of 1 to 30 mm to give a straight grain pattern. Method. 4. The molding resin material is a thermoplastic resin 100.
The method for producing a synthetic resin plate having a wood grain pattern according to any one of claims 1 to 3, wherein a mixture obtained by further mixing 10 to 100 parts by weight of wood flour with respect to parts by weight is used.